DVI cable interface

[0001] This invention relates to interfaces for electrical devices. In particular, the invention relates to cable to Digital Visual Interface (DVI) for use with digital display devices. With still greater particularity, the invention relates to interconnect boards for connecting a DVI interface to multiple cables.

[0002] A portion of the disclosure of this patent document contains material which is subject to (copyright or mask work) protection. The (copyright or mask work) owner has no objection to the facsimile reproduction by any one of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all (copyright or mask work) rights whatsoever.

[0003] The Digital Visual Interface (DVI) is a display interface developed in response to the proliferation of digital flat-panel displays. The DVI interface is becoming more prevalent and is expected to become widely used for digital display devices, including flat-panel displays and emerging digital CRTs. The digital DVI connector has 24 pins that can accommodate up to two TMDS links and the VESA DDC and EDID services. The DVI specification defines two types of connectors. The standard DVI cable attachable to the connector is a 24-conductor cable. DVI cables are expensive and cannot be used for great lengths. The longest commercially available DVI cable is sixteen feet in length (16′).

[0004] The only available alternative to use of DVI cables is double digital analog conversion. The digital signal from the computer must be converted to an analog signal for the analog VGA interface, then converted back to a digital signal for processing by the flat-panel display. This inherently inefficient process takes a toll on performance and video quality and adds cost. In contrast, when a display is directly connected to a digital interface, digital-to-analog conversion is not required.

[0005] A suitable DVI cable arrangement is an essential element of a new generation of electronic devices including digital television, High Definition Television (HDTV) and large data monitors. Such devices will need long cables as the display is often removed from the electronics.

[0006] A problem has arisen in DVI technology where a digital signal is required to traverse a long distance. The bandwidth required to display SXGA is 83 MHZ. If a greater resolution, such as for HDTV, is desired, the bandwidth requirement will be correspondingly larger. If standard 24-conductor cable is used, the crosstalk and radiation along with capacitive degradation of signal making the use of long length DVI cables untenable. Accordingly, there is a long-standing demand for DVI cable system capable of long length and reasonable cost.

[0007] The invention makes extensive use of existing time proven cabling methods. A standard DVI interface connector of one gender is connected to a custom connector card. The card connects the 24 output connections of the interface to a plurality of twisted pair cables. A similar card connects the twisted pair cables to a DVI connector of the opposite gender.

[0008] The inventions system allows connection of devices such as displays to a remote source such as a television receiver or computer. This is accomplished with time-tested components at minimal cost. The invention may be used to string the twisted pair cables through walls with a converter at each end attachable by DVI pigtail to the components.

[0011] FIG. 1 is a block diagram of the system of the invention. The component source is the source of the DVI signal. Component source 1 may be a computer, specifically, the video output of a computer. Component source 1 may also be a DVD, player, a television set, or VCR, in short, any thing that is capable of producing a signal under the DVI standard. Component source 1 typically delivers the signal through a standard DVD jack, although a direct connection to a DVI cable is also possible. One end of a DVI cable 2 connects to the output of component source 1. Cable 2 is typically a 24 four-wire cable adapted specifically for transmission of DVI signals. The other end of cable 2 connects to a converter 3. The connection of cable 2 to converter 3 may be done through a DVI plug and DVI jack or may be direct. Converter 3 converts the 24-input signal into a plurality of signals suitable for twisted pair cables. In the preferred embodiment, converter 3 does not include any active components. In the preferred embodiment, converter 3 outputs to three RJ45 jacks. A plurality of twisted pair cables 4 have one end connected to converter 3. In the preferred embodiment, three category 5 cables each having four twisted pairs was used for cables 4. For a greater bandwidth, category 5E or an optimized cable should be used. “110” telephone style punch down blocks should be used instead of the RJ45 connectors as output jacks 37, 38, and 39 if cables 4 uses 20 GA solid conductors which won't fit an RJ45. The other end of cables 4 connect to the input of a second converter 5. In the preferred embodiment, converter 5 is identical to converter 3 reversed. The output of converter 2 connects to a DVI cable 6. DVI cable connects to a peripheral 7. Peripheral 7 may be a video monitor or any device having a DVI input.

[0012] FIG. 2 is a top plan view of converter 3 of the invention. A printed circuit board 10 forms the body of converter 3. Converter 3 includes a DVI jack 11 mounted to the back side of printed circuit board 10 for inputting a DVI signal. A Molex DVI-D Female Receptacle p#74320-5000 has been found suitable for jack 11 but other equivalent jacks could be used. Jack 11 includes 24 pin recepticles 12–36. Three output jacks 37, 38, and 39 are also mounted to printed circuit board 10 included on converter 3. Molex CAT5 Jack w/internal shield #855070001 have been found suitable for use as output jacks 37, 38, and 39. In particular, “110” telephone style punch down blocks should be used instead of the RJ45 connectors as output jacks 37, 38, and 39 if cables 4 uses 20 GA solid conductors which won't fit an RJ45. Each of output jacks 37, 38, and 39 include 8 pins 40–47, 50–57 and 60–67, respectively. Board 10 connects pin 12 of input DVI jack 11 to pin 40 of output jack 37. The remaining pins are connected as shown in the following table.

• [0013] Jack 37 pin 40 to DVI jack 11 pin 12 T.M.D.S. Data 2−signal
• [0014] Jack 37 pin 41 to DVI jack 11 pin 13 T.M.D.S. Data 2+signal
• [0015] Jack 37 pin 42 to DVI jack 11 pin 14 T.M.D.S. Data 2/4 Shield
• [0016] Jack 37 pin 43 to DVI jack 11 pin 15 T.M.D.S. Data 2−signal
• [0017] Jack 37 pin 44 to DVI jack 11 pin 16 T.M.D.S. Data 4+signal
• [0018] Jack 37 pin 45 to DVI jack 11 pin 17 DDC Clock
• [0019] Jack 37 pin 46 to DVI jack 11 pin 18 DDC Data
• [0020] Jack 37 pin 47 to DVI jack 11 pin 19 Analog Vertical Sync.
• [0021] Jack 38 pin 50 to DVI jack 11 pin 20 T.M.D.S. Data 1−signal
• [0022] Jack 38 pin 51 to DVI jack 11 pin 21 T.M.D.S. Data 1+signal
• [0023] Jack 38 pin 52 to DVI jack 11 pin 22 T.M.D.S. Data 1/3 Shield
• [0024] Jack 38 pin 53 to DVI jack 11 pin 23 T.M.D.S. Data 3−signal
• [0025] Jack 38 pin 54 to DVI jack 11 pin 24 T.M.D.S. Data 3+signal
• [0026] Jack 38 pin 55 to DVI jack 11 pin 25+5 volts
• [0027] Jack 38 pin 56 to DVI jack 11 pin 26 Ground
• [0028] Jack 38 pin 57 to DVI jack 11 pin 27 Hot plug direct
• [0029] Jack 39 pin 60 to DVI jack 11 pin 28 T.M.D.S. Data 0−signal
• [0030] Jack 39 pin 61 to DVI jack 11 pin 29 T.M.D.S. Data 0+signal
• [0031] Jack 39 pin 62 to DVI jack 11 pin 30 T.M.D.S. Data 0/5 Shield
• [0032] Jack 39 pin 63 to DVI jack 11 pin 31 T.M.D.S. Data 5−signal
• [0033] Jack 39 pin 64 to DVI jack 11 pin 32 T.M.D.S. Data 5+signal
• [0034] Jack 39 pin 65 to DVI jack 11 pin 33 T.M.D.S. Clock shield
• [0035] Jack 39 pin 66 to DVI jack 11 pin 34 T.M.D.S. Clock +
• [0036] Jack 39 pin 67 to DVI jack 11 pin 35 T.M.D.S. Clock −

[0037] A modified converter 3 may be mounted in a wall socket (not shown) with DVI jack 11 pointing into the room and jacks 37, 38, and 39 directed toward the wall. Long cables 4 running through walls can connect two such converters to allow an unobtrusive remote monitor in a building. DVI cables 2 and 6 are pigtails connecting to source 1 and output 7 respectively.

[0038] The present invention may be used to solve problems that have arisen in DVI technology where a digital signal is required to traverse a long distance. The invention allows connection of devices such as displays to a remote source such as a television receiver or computer. The invention uses a standard DVI interface connector of one gender connected to a custom connector card. The card connects the 24 output connections of the interface to a plurality of twisted pair cables. A similar card connects the twisted pair cables to a DVI connector of the opposite gender.

[0039] The present invention has been particularly shown and described with respect to certain preferred embodiments and features thereof. However, it should be readily apparent to those of ordinary skill in the art that various changes and modifications in form and detail may be made without departing from the spirit and scope of the inventions as set forth in the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more”. The inventions illustratively disclosed herein may be practiced without any element which is not specifically disclosed herein.